The only known repeating fast radio bursts may originate from a neutron star in an extreme environment, according to a study published in Nature this week.

Fast radio bursts are millisecond-duration, extragalactic radio flashes of unknown physical origin. The only known source of repeating fast radio bursts, called FRB 121102, has been localized to a star-forming region in a dwarf galaxy with a redshift (a parameter used to indicate distance) of approximately 0.2. However, the origin of the bursts, the nature of the source and the properties of the local environment are still debated.

Jason Hessels and colleagues detected 16 bursts from FRB 121102 using the William E. Gordon Telescope at the Arecibo Observatory. The authors found that the bursts had a very high and variable Faraday rotation measure - rotation of the plane of polarization of the radio waves as they pass through a magnetic field in plasma. These findings suggest that FRB 121102 is in an environment with an extremely high magnetic field and temperature, and previously such conditions have been observed only in the vicinity of massive black holes; however, other models may also explain these properties. The authors note that the short duration of the bursts could imply they come from a neutron star in such an environment.

The authors speculate that the markedly higher activity level of FRB 121102 compared to other fast radio bursts is predominantly a consequence of the environment in which it is found.